1. Field of the Invention
The present invention generally relates to a vehicle drive force distributing apparatus. More particularly, the present invention relates to a frictional transmission type vehicle drive force distributing apparatus that is capable of reducing energy consumption when distributing drive force between a main drive wheel and a subordinate drive wheel.
2. Background Information
A vehicle drive force distributing apparatus operates to distribute drive force between a main drive wheel and a subordinate drive wheel. For example, Japanese Laid-open Patent Publication No. 2009-173261 discloses an example of a conventional frictional transmission type drive force distributing apparatus. As shown, for example, in FIG. 5, the drive force distributing apparatus includes a first roller that is mechanically coupled to a main drive wheel, and a second roller that is mechanically coupled to a subordinate drive wheel. The apparatus operates to position the first roller and the second roller to make frictional contact with each other at their outer circumferential surfaces to redistribute a portion of a torque being transmitted to the main drive wheel from the main drive wheel to the subordinate drive wheel.
Accordingly, a torque transmission capacity between the rollers can be controlled by adjusting a radially oriented pressing force between the first roller and the second roller. The torque transmission capacity therefore controls the distribution of the drive force between the main drive wheel and the subordinate drive wheel.
In particular, the apparatus controls a motor or the like to turn a rotary shaft of the second roller about an eccentric axis such that the second roller is displaced in a radial direction with respect to the first roller. In this way, the apparatus adjusts the radial pressing force between the first roller and the second roller. Accordingly, the apparatus controls distribution of the drive force between the main drive wheel and the subordinate drive wheel.